Adjustable anchor device for furnace walls

ABSTRACT

An improved anchor device for securing refractory linings to furnace walls, the device comprising a ceramic holding cap enclosing an upper extension of a ceramic anchor attached to the furnace wall. The holding cap is slideably movable upon the ceramic anchor and may be adjusted to compensate for various thicknesses of lining materials and to compensate for dimensional changes in the lining materials during furnace operation.

United States Patent [191 Sweet Nov. 13, 1973 ADJUSTABLE ANCHOR DEVICEFOR FURNACE WALLS [75] Inventor: Larrie H. Sweet, Ransomville, NY.

[73] Assignee: The Carborundum Company,

Niagara Falls, N.Y.

[22] Filed: Aug. 30, 1972 [21] Appl. No.: 285,390

[52] US. Cl 110/1 A, 52/506, 122/6 A [51] Int. Cl. F23m 5/00 [58] Fieldof Search 110/1 R, 99 R; 52/249, 506, 712, 714, 378, 443, 444, 700,

[56] References Cited UNITED STATES PATENTS Byrd, Jr. 52/506 Wildish52/506 Finley 52/506 Primary Examiner-Kenneth W. Sprague AssistantExaminerLarry I. Schwartz Attorney-David E. Dougherty et al.

[57] ABSTRACT An improved anchor device for securing refractory liningsto furnace walls, the device comprising a ceramic holding cap enclosingan upper extension of a ceramic anchor attached to the furnace wall. Theholding cap is slideably movable upon the ceramic anchor and may beadjusted to compensate for various thicknesses of lining materials andto compensate for dimensional changes in the lining materials duringfurnace operation.

7 Claims, 5 Drawing-Figures PATENTED BUY 13 I973 FIG.2

FIG.

FIG.3

FIG. 4

FIG. 5

ADJUSTABLE ANCHOR DEVICE FOR FURNACE WALLS BACKGROUND OF THE INVENTIONThis invention relates to the construction, especially the lining, offurnace walls and is particularly concerned with installations utilizingblankets, bats, or blocks of relatively lightweight refractory or heatinsulating materials usable at relatively high temperatures.

Many methods and devices have been previously suggested for securingrefractory and/or insulating materials as linings to the interior wallsof a furnace. In many of such methods or devices the lining is requiredto have a specific shape or elaborate hardware on the furnace walls isrequired. In many instances an exorbitant amount of labor is necessary.Consequently, there has been a demand for a construction which permitsthe convenient attachment of refractory and/or insulating material inthe form of blankets, sheets, bats, or blocks to furnace walls with aminimum of hardware and accessories and without exposing mountinghardware to furnace atmosphere and temperature.

A furnace wall construction as described in patent application Ser. No.142,168, filed May 12, 1971, provides a simple and convenient method forlining furnace walls by securing blankets, sheets, blocks, or bats ofsuitable refractory and/or heat-insulating material on the walls, eitherin a single layer or in a plurality of layers. In constructing orinstalling the lining the securing or mounting means may be readilyapplied wherever necessary or desired, thus giving a flexibility tofurnace wall construction which is absent in many prior systems.

Essentially the mounting or securing devices utilized in the method ofthis construction consist of tubular ceramic retaining members and smallmetal bushings. Each bushing is adapted to be secured to a metal wallsurface and to so engage an associated one of the tubular ceramicretainers as to hold it against the wall surface. The metal bushings areplaced inside the tubular ceramic members (hereinafter for conveniencereferred to as anchors") the bushings and anchors having interengagingbevelled portions, and secured by suitable means, such as welding, tothe metal furnace wall. The anchor is thus supported on the furnacewall, extending outwardly therefrom and having such externalconfiguration as to engage the body of refractory and/or insulatingmaterial. The outer extensions of the anchors may have suitable flangesfor engaging the outer face of the furnace lining material or theanchors may be shaped to engage refractory washers which in turn restupon the outer face of the lining material. While this anchoring systemas described has been quite successful, it has a disadvantage in thatthe lengths of the ceramic anchors cannot be readily adjusted to conformto varying thicknesses of lining material. Some types of fibrous liningmaterial may be compressed to some degree during installation, but thedenser types will not. This means the ceramic anchors used must havelengths closely matching the thickness of the lining materials used.Thicker liners will put a high mechanical strain on the anchors, whilethinner liners will not be held tightly enough to avoid sagging andshifting. The furnace liners may also shrink during service and theceramic anchors used cannot compensate for this. It is thereforedesirable, in a system of this type, to provide an improved anchor whichmay be easily adapted to changes in the thickness of the liningmaterials and which can compensate to some degree for dimensionalchanges occuring in these materials during furnace operations.

SUMMARY OF THE INVENTION The invention provides an improved ceramicanchor device which comprises a ceramic holding cap which surrounds anouter extension of a ceramic anchor and is slideably moveable thereon.The ceramic holding cap may have an outwardly extending flange at itsupper end for engagement with the outer face of a furnace liningmaterial. The holding cap may alternatively engage a washer of ceramicmaterial which holds the outer face of the lining material. The overalllength of the ceramic anchor and holding cap may be adjusted by applyingone or more rings or gaskets of compressible refractory fibrous materialaround the outer extension of the anchor, before it is surrounded by theceramic holding cap, these rings allowing not only adjustment of theoverall length of the anchor device, but also a continuing pressure ofthe holding cap against the lining material, due to the elasticity ofthe fibrous rings.

DESCRIPTION OF THE DRAWINGS FIG. 1 shows a ceramic anchor in place on afurnace wall and fastened to the wall by an internal metal bush- FIG. 2shows the improved ceramic holding cap.

FIG. 3 shows the improved ceramic holding cap in position upon theceramic anchor of FIG. 1 to give an adjustable anchor device.

FIG. 4 shows the holding action of the adjustable anchor device upon abody of lining material.

FIG. 5 shows an alternate holding cap construction, using a separableceramic washer as a holding surface.

DESCRIPTION OF THE INVENTION This invention is an improvement over amethod described in patent application, Ser. No. 142,168, filed May 12,1971, for securing lining materials, such as refractory or ceramicinsulation panels, to metal furnace walls. In this method, suitableholes are cut in the lining material and cylindrical ceramic anchors arethen positioned in these holes and fastened to the underlying furnacewall by welding or otherwise securing suitable metal bushings insertedwithin the ceramic anchor. This method is generally indicated in FIG. 1where the underlying metal furnace wall is shown at 10 and the ceramicanchor 12 is fastened to the wall by means of a conical metal bushing 14which firmly wedges into a correspondingly shaped surface inside theanchor 12. The bushing 14 is fastened to wall 10 by welding at 15. In analternate method, the bushing may be threaded for engagement with amatching threaded short stud fastened at 10. The ceramic anchor 12 has,at its upper extension, a radial flange extending outwardly at 13. Theimproved anchor device comprises a ceramic holding cap 18, as shown inFIG. 2 in combination with the ceramic anchor as shown in FIG. 1. At thelower end, the cap 18 has a radial flange 20, extending inwardly, withan inside opening having a diameter slightly larger then the outsidediameter of the ceramic anchor 12, shown in FIG. 1. The improved deviceis shown in FIG. 3 where the ceramic cap 18 is shown assembled in asliding relationship with the upper extension of the ceramic anchor 12.The overall length of the attachment device may be readily adjusted byplacing one or more rings or gaskets of flexible refractory material 21around ceramic anchor 12 before the addition of the ceramic holding cap18. In FIG. 4, the anchor device is shown attached to the underlyingfurnace wall 10, with the holding cap 18 securing layers of liningmaterial 22. The outer end of the cap has an integral outwardlyextending annular flange 24 which engages the outer face of the liningmaterial.

An alternate construction for the holding cap 18 is shown in FIG. inwhich the cap 18 has an outardly sloping exterior bevel surface at 26,whereby a separate ceramic washer 28 is engaged by a matching bevelsurface on the center opening of the washer.

The overall length of the improved anchor device may be easily adjustedto fit various thicknesses of lining materials by adding rings orgaskets of resilient f1- brous material around the upper extension ofthe ceramic anchor, as shown in FIGS. 3 and 4. The fibrous material 21may be in the form of a braid or rope and may comprise refractory fiberssuch as those of aluminum silicate, alumina, silica, zirconia, boroncarbide, silicon carbide and the like. The material should havesufficient resiliency to exert a compressive effect upon the liningmaterials when the attachment device is installed. This effect tends tocompensate for dimensional changes in the lining during furnaceoperation and provides an automatic compensation for variations inlining thickness, both before and during furnace operation.

A further advantage of the improved attachment device is in the use of astandard, relatively short, ceramic anchor, as shown in FIG. 1. Thistype of ceramic anchor can now be used in many different types ofapplications, the shorter length making installation easier. While thesame refractory may be used for both the ceramic anchor and the holdingcap, this is not essential to the invention and the holding cap may bemade of a more heat resistant refractory, if desired. The open centerportions of both the ceramic anchor and the holding cap are preferablypacked with bulk ceramic fiber to reduce heat transfer and protect themetal bushing 14 (FIG. I and 4) against the furnace heat. Refractorycaps or castable mixes would not be satisfactory for this purpose sincethey would probably interfere with the adjustable action of the anchordevice. For additional insulation, the annular open space 30 (FIG. belowthe holding cap base is also filled with a cylinder of light weightcompressible refractory fiber, preferably an aluminum silicate fiber.

The anchor device of the invention is assembled by sliding the ceramicholding cap 18, shown in FIG. 2 over the ceramic anchor 12, the flangeof the holding cap being retained by the flange 13 of the ceramicanchor. One or more rings of compressible fibrous refractory material 21are preferably placed around the body of furnace lining material and theceramic anchor fastened to the furnace shell by a metal insert 14,secured to the shell, preferably by welding, as shown in FIG. 4. A smallcylinder of compressible refractory fibrous insulation may be placedaround the ceramic anchor before it is fastened in place and the hollowinteriors of both anchor and holding cap may be filled with a similarinsulation to reduce heat loss.

What is claimed is:

1. In a furnace wall having a metal surface; a furnace lining materialon said surface, said lining material having an inner face adjacent saidsurface and an outer face, a tubular ceramic anchor fastened to thesurface and extending through the lining material to secure it to saidsurface; the improvement comprising a ceramic holding cap surrounding anouter extension of the ceramic anchor and slideably movable thereon,said holding cap having means for engaging the outer face of the liningmaterial and means for adjusting the holding force applied to the outerface of the lining material.

2. A furnace wall according to claim 1 in which the engaging meanscomprises an outwardly extending radial flange.

3. A furnace wall according to claim 1 in which the engaging meanscomprises a washer of ceramic material.

4. A furnace wall according to claim 1 in which the adjusting meanscomprises at least one ring of compressible fibrous refractory material.

5. A furnace wall according to claim 4 in which the refractory fibrousmaterial is selected from the group consisting of aluminum silicate,alumina, silica, zirconia, boron carbide and silicon carbide.

6. A method of installing a lining on a metal furnace wall whichcomprises;

a. providing a body of furnace lining material, the

body having an inner face and an outer face;

b. forming an opening through said body;

c. insertinginto said opening from the outer face of said body a tubularceramic anchor, said anchor having a slideably movable ceramic holdingcap surrounding an outer extension of the anchor, the holding capengaging the outer face of the body;

(1. inserting a metal bushing into said anchor; and

e. securing said metal bushing to the metal funace wall, the bushingengaging with an inner extension of the anchor to hold the anchoragainst the furnacewall.

7. A method of installing a lining on a metal furnace wall according toclaim 6 in which the method further comprises:

f. forming at least one ring of compressible fibrous refractory materialaround the outer extension of the anchor; and

g. inserting the anchor within the movable ceramic holding cap beforethe insertion of the anchor into the opening in the body of liningmaterial at step

1. In a furnace wall having a metal surface; a furnace lining materialon said surface, said lining material having an inner face adjacent saidsurface and an outer face, a tubular ceramic anchor fastened to thesurface and extending through the lining material to secure it to saidsurface; the improvement comprising a ceramic holding cap surrounding anouter extension of the ceramic anchor and slideably movable thereon,said holding cap having means for engaging the outer face of the liningmaterial and means for adjusting the holding force applied to the outerface of the lining material.
 2. A furnace wall according to claim 1 inwhich the engaging means comprises an outwardly extending radial flange.3. A furnace wall according to claim 1 in which the engaging meanscomprises a washer of ceramic material.
 4. A furnace wall according toclaim 1 in which the adjusting means comprises at least one ring ofcompressible fibrous refractory material.
 5. A furnace wall according toclaim 4 in which the refractory fibrous material is selected from thegroup consisting of aluminum silicate, alumina, silica, zirconia, boroncarbide and silicon carbide.
 6. A method of installing a lining on ametal furnace wall which comprises; a. providing a body of furnacelining material, the body having an inner face and an outer face; b.forming an opening through said body; c. inserting into said openingfrom the outer face of said body a tubular ceramic anchor, said anchorhaving a slideably movable ceramic holding cap surrounding an outerextension of the anchor, the holding cap engaging the outer face of thebody; d. inserting a metal bushing into said anchor; and e. securingsaid metal bushing to the metal funace wall, the bushing engaging withan inner extension of the anchor to hold the anchor against the furnacewall.
 7. A method of installing a lining on a metal furnace wallaccording to claim 6 in which the method further comprises: f. formingat least one ring of compressible fibrous refractory material around theouter extension of the anchor; and g. inserting the anchor within themovable ceramic holding cap before the insertion of the anchor into theopening in the body of lining material at step (c).